4 -20• To improve speed response and stability in V/f control with a PG (A1-02 = 1), set the ASR constants (C5-01 to C5-05) to between 0.5 and 1.5 times the default. (It is not normally necessary to adjust this setting.)ASR for V/f control with a PG will only control the output frequency; a high gain, such as is possible foropen-loop vector control, cannot be set.The following user constants will also indirectly affect the control system.Table 4.6 Constants Indirectly Affecting Control and ApplicationsName (Constant Number) ApplicationCT/VT selection (C6-01) Sets the maximum torque and overload capability to 120% or 150%.DWELL function (b6-01 to b6-04) Used for heavy loads or large machine backlashes.Droop function (b7-01 to b7-02) Used to soften the torque or to balance the load between two motors. Canbe used when the control method (A1-02) is set to 3.Acceleration/deceleration times(C1-01 to C1-11) Adjust torque during acceleration and deceleration.S-curve characteristics (C2-01 to C2-04) Used to prevent shock when completing acceleration.Jump frequencies (d3-01 to d3-04) Used to avoid resonance points during operation.Analog input filter time constant (H3-12) Used to prevent fluctuations in analog input signals caused by noise.Stall prevention (L3-01 to L3-06,)Used to prevent 0 V (overvoltage errors) and motor stalling for heavyloads or rapid acceleration/deceleration. Stall prevention is enabled bydefault and the setting does not normally need to be changed. When usinga braking resistor, however, disable stall prevention during decelerationby setting L3-04 to 0.Torque limits (L7-01 to L7-04,)Set the maximum torque during vector control. If a setting is increased,use a motor with higher capacity than the Inverter. If a setting is reduced,stalling can occur under heavy loads.Feed forward control (N5-01 to N5-04)Used to increase response for acceleration/deceleration or to reduce over-shooting when there is low machine rigidity and the gain of the speedcontroller (ASR) cannot be increased. The inertia ratio between the loadand motor and the acceleration time of the motor running alone must beset.L3-11, L3-12L7-06, L7-07
